[withdrawn] mm-dmapoolc-avoid-duplicate-memset-within-dma_pool_alloc.patch removed from -mm tree

[withdrawn] mm-dmapoolc-avoid-duplicate-memset-within-dma_pool_alloc.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm/dmapool.c: avoid duplicate memset within dma_pool_alloc
has been removed from the -mm tree.  Its filename was
     mm-dmapoolc-avoid-duplicate-memset-within-dma_pool_alloc.patch

This patch was dropped because it was withdrawn

------------------------------------------------------
From: Liu Song <liusong@linux.alibaba.com>
Subject: mm/dmapool.c: avoid duplicate memset within dma_pool_alloc
Date: Mon, 18 Jul 2022 14:28:10 +0800

From: Liu Song <liusong@linux.alibaba.com>

In "dma_alloc_from_dev_coherent" and "dma_direct_alloc",
the allocated memory is explicitly set to 0.

A helper function "use_dev_coherent_memory" is introduced here to
determine whether the memory is allocated by "dma_alloc_from_dev_coherent".

And use "get_dma_ops" to determine whether the memory is allocated by
"dma_direct_alloc".

After this modification, memory allocated using "dma_pool_zalloc" can avoid
duplicate memset.

Link: https://lkml.kernel.org/r/1658125690-76930-1-git-send-email-liusong@linux.alibaba.com
Signed-off-by: Liu Song <liusong@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/dma-map-ops.h |    5 +++++
 mm/dmapool.c                |    5 ++++-
 2 files changed, 9 insertions(+), 1 deletion(-)

--- a/include/linux/dma-map-ops.h~mm-dmapoolc-avoid-duplicate-memset-within-dma_pool_alloc
+++ a/include/linux/dma-map-ops.h
@@ -183,6 +183,10 @@ int dma_alloc_from_dev_coherent(struct d
 int dma_release_from_dev_coherent(struct device *dev, int order, void *vaddr);
 int dma_mmap_from_dev_coherent(struct device *dev, struct vm_area_struct *vma,
 		void *cpu_addr, size_t size, int *ret);
+static inline bool use_dev_coherent_memory(struct device *dev)
+{
+	return dev->dma_mem ? true : false;
+}
 #else
 static inline int dma_declare_coherent_memory(struct device *dev,
 		phys_addr_t phys_addr, dma_addr_t device_addr, size_t size)
@@ -194,6 +198,7 @@ static inline int dma_declare_coherent_m
 #define dma_release_from_dev_coherent(dev, order, vaddr) (0)
 #define dma_mmap_from_dev_coherent(dev, vma, vaddr, order, ret) (0)
 static inline void dma_release_coherent_memory(struct device *dev) { }
+#define use_dev_coherent_memory(dev) (0)
 #endif /* CONFIG_DMA_DECLARE_COHERENT */
 
 #ifdef CONFIG_DMA_GLOBAL_POOL
--- a/mm/dmapool.c~mm-dmapoolc-avoid-duplicate-memset-within-dma_pool_alloc
+++ a/mm/dmapool.c
@@ -21,6 +21,7 @@
 
 #include <linux/device.h>
 #include <linux/dma-mapping.h>
+#include <linux/dma-map-ops.h>
 #include <linux/dmapool.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
@@ -372,7 +373,9 @@ void *dma_pool_alloc(struct dma_pool *po
 #endif
 	spin_unlock_irqrestore(&pool->lock, flags);
 
-	if (want_init_on_alloc(mem_flags))
+	if (want_init_on_alloc(mem_flags) &&
+		!use_dev_coherent_memory(pool->dev) &&
+		get_dma_ops(pool->dev))
 		memset(retval, 0, pool->size);
 
 	return retval;
_

Patches currently in -mm which might be from liusong@linux.alibaba.com are